Sheet stacking apparatus



July 27, 1965 G. A. B. BYRT SHEET STACKING APPARATUS 4 Sheets-Sheet 1Filed Jan.- 21, 1965 wwavroz ,47'7'ORA/E/5 July 27, 1965 G. A. B. BYRT3, 97, 00

. SHEET STAGKING APPARATUS Filed Jan. 21, 1963 4 Sheets-Sheet 2 470m 4/5@10 8) mm mwm/zz July 27, 1965 G. A. B. BYRT SHEET STACKING APPARATUS 4Sheets-Sheet 4 Filed Jan. 21, 1963 United States Patent .0

J 4 Claims. ci. 271-4 This invention concerns improvements in sheetstacking apparatus such as is used on printing and other machines wheresheets emerging from the machine are collected in stacks or piles, andconsists in devices for forming stacks containing a definite number ofsheets.

The apparatus for stacking sheets is of the kind comprising means forfeeding sheets in succession along a path, a rotatable suction rollermounted adjacent said path and arranged to remove the sheets insuccession therefrom, stripping means associated with the roller toremove each sheet therefrom and a stacker adapted to receive thestripped sheets and stack them and counting of the sheets forming into astack is effected by a valve operated by a counting device moving insynchronism with the suction roller, to shut off the roller completelyfrom a source of suction so as to stop suction through the rollerperiphery at the position adjacent the aforesaid path where the rollerremoves a sheet from said path, after the suction roller has rotated adesired number of revolutions and has thus stacked a desired number ofsheets.

When the valve has operated to completely shut off a source of suctionfrom the suction roller, the sheets may continue to move in successionalong the path to a second suction roller and associated stacker so thata secon stack is formed and, after the first suction roller has againrotated through the desired number of revolutions, the valve operates toconnect it again to the source of suction. In this way each stackercollects the same number of sheets and one stacker may be emptied whilethe other is being filled. I

Generally speaking it is preferable to cut sheets from a moving web at aposition somewhat in advance of the first suction roller but theapparatus is not limited to such a method as it can be used to stackpiles of sheets which have been fed to the printing or other machine asseparate sheets.

The invention will be described by way of example with reference. to theaccompanying drawings in which:

FEGURE 1 is a diagram of a machine embodying the sheet stackingapparatus,

FIGURE 2 is a cross-section of part of such a machine showingsuction-roller valve control devices, part of a suction roller, and arotary valve for shutting off a source of suction from the roller, allin section,

FIGURE 3 is a section of FIGURE 2 on the line 3-3,

FIGURE 4 is a cross-section through a suction roller,

FIGURE 5 shows a driving device for a ratchet wheel for operating therotary valve.

Referring to FIGURE 1 a web ll coming from a printing machine passesinto a cutting device comprising a rotary knife head 2 and a fixed knife3 which cooperates with the moving knives 3A to cut sheets from themoving web. The edges of the knives are canted in the known manner toobtain a shearing cut across the width oi the web. The web is thus cutinto a succession of following sheets but normally a wide web is usedand this is first slit into narrower Webs by slitting knives 4 cuttingagainst a roller 5 and thus a number of side-by-side sheets are cut atonce. For simplicity of explanation it will, however, be assumed thatthe web is merely cut into a succession of following sheets. A cut sheetis engaged by a feeding roller 6 and a co-operating pressure roller 7and moves along a path P which is substantially defined by a plate 8through which the roller 6 protrudes. Similar pairs of rollers, 9 toM-inclusive, similarly arranged, carry the sheet onwards untileventually it comes into C011, tact with a suction roller 15, and acooperating pressure roller 16. The feeding rollers run at a peripheralspeed higher than the web speed to space the sheets apart. The suctionroller will be described in detail later with reference to FIGURES 2 to4 but for the moment it is sulficient to say that it is provided withsuction control valve arrangements operated by the rotation of theroller, as is usual in this kind of apparatus, and seizes a sheet by itssuction efiect and carries it through about to a stripping position at17. A belt 18 runs in a groove in the periphery of the roller 15 so asto lie inside the periphery, said belt passing over guide rollers 19 and2t and a tightening roller 21. For wide sheets there are several beltsl8 and corresponding grooves. It will be seen from the figure that theupper run of the belt 13 leaves the suction roller 15 at a tangent andwill thus strip a sheet from the roller. To facilitate the strippingaction and avoid injury to the sheet the suction is cut offprogressively as each portion of the suction roller periphery, in turn,approaches the stripping position. Above that position is a stacker 22.

As will be seen from the drawing, the relative positions of the suctionroller 15 and the stacker 22 are such that the sheets in the stacker, atthat side where sheets enter the stacker, overhang the top part of theroller by some distance and the gap between the following part of theroller and the lowest sheet in the stacker forms a kind of wedge-shapedor converging entry or mouth. This permits each successive sheet to passinto the stacker beneath the lowest sheet in the stack, the sheetmovement being imparted partly by drive from the suction roller andpartly by the belt 18.

in order to assist in maintaining the sheets in a neat ice stack, apivoted fence 22A is provided. This may be lifted manually, when a stackis to be removed, but it may be moved automatically as related later.The plate 223 against which the sheets form into a stack is grooved topass over the belt and provide small projections below the level of thebelt so that the plate forms an effective stop for the sheets. p

In order to have piles of a definite number of sheets, means areprovided to shut off a source of suction from the roller 15 at givenintervals. number of sheets has accumulated in the stacker 22, thesuction in roller 15 for picking up the sheets from path P is completelystopped for a time, as related later, so further sheets, instead ofbeing stacked at 22, continue to move along the path P under theinfluence of feeding and pressure rollers 23 to 26 inclusive, untilanother suction roller 27, having a pressure roller 23, is reached. Thissuction roller is arranged for convenience of operation to feed sheetsinto a downwardly descending pile in another stacker 29, the sheetsbeing stripped from the drum by a plate 29A having a curved and taperedend 293 which lies inside the periphery of the suction roller and ahorizontal part tangential to the periphery of the roller. The stackerhas a ba-seplate 30 which moves down in guides 31 as each fresh sheet isfed into the'stacker. Control of the base plate movement may be effectedby an air cylinder 32, which is filled with fairly low pressure air toraise the base plate to its top position and has a bleeder valve (notshown) which permits air to escape as the base plate is to be moveddownwards. The cylinder has a piston rod 33 connected to a bell-cranklever 34 having a link 35 at the end of its longer arm, which link ispivoted to the base plate. In an alternative arrangement (not shown) theplate may be balanced by a balance weight' which is sufficient to holdthe plate in the up position but ermits the plate to move downwardsunder the thrust of incoming sheets fed into the stacker. As in the caseof the stacker 22, the suction roller 27 and stacker 29 are Thus, aftera desired so arranged that the sheets in the stacker extend beyond theroller and a wedge-shaped mouth or entry is formed, as before, so thateach successive sheet easily runs over the preceding sheet in the stack.

The shutting off of a source of suction from the roller 15 so that theroller no longer picks up sheets can be followed from FIGURES 2 and 3which show portions of the valve arrangements to a large scale.Referring first to FIGURE 2 a ratchet wheel 45) is rotated 21 tooth at atime by a slow moving cam '79, FIGURE 5. Assuming each counted pile isto have 500 sheets, the cam rotates once for each 50 sheets passing tothe stacker and thus ten cam strokes mean that 500 sheets have passed.The ratchet wheel has twenty teeth and it will be moved through tenteeth by the ten cam strokes, or half a revolution. A rotary valve disc41 is attached to the ratchet wheel and it has a perforation at 42. Asshown, this is aligned with a hole 43 leading to a suction pipe 44 (thecounting suction pipe) and, ignoring other things, it will be understoodthat a small rotation of the valve disc 41 would shut off the rollerfrom the suction pipe 44. The hole 43 is however in communication withan arcuate slot 44A so that a considerable movement of the disc isnecessary before the suction roller 15 is shut off from the suction pipe44. It will be noticed that in the drawing the valve disc 41 is shown asby-passcd by passages 61, controlled by a valve 60, but the purpose ofthis is explained later. It is a manually operated valve but duringregular sheet counting operations it is closed. Because of the slot 44Athe hole 43 is for some time in communication with another passage 45and a pipe 46 which leads to a valve arrangement attached to the suctionroller 15, and operated by the roller rotation, which will now beexplained with reference also to FIGURE 3. 47 is the shaft of thesuction roller 15 which rotates in the direction of the arcow R, FIGURES3 and 4. To the shaft is fixed a valve piece 48 having two sets ofpassages 49, as shown, and this valve piece rotates in a fixed bush 5t)having a slot 51 which extends over the are A and with which the pipe 46communicates. As the valve piece 48 rotates, one set of its passages 49pass across the slot 51 and are thus connected to the counting suctionpipe 44 through the pipe 46. Another slot 52 is made in the bush 50 andextends over the arc B. There is an overlap C between the arcs whosepurpose is explained below.

Therefore as the valve piece 43 rotates, its other set of passages 49pass across this slot 52, as can be seen from FIGURE 2, and connect to afurther suction pipe 53 (the stacking suction pipe). The terms countingand stacking in respect of the pipes 44 and 53 are used as convenientdistinguishing terms for ease of explanation although, as will be seenlater, both suction pipes are concerned at times with delivery of sheetsto the first stacker, 22, FIGURE 1.

Along the length of the suction roller are passages 54, FIGURE 2, whoseshape is best seen in FIGURE 4, and explained in more detail withreference to that figure. The part marked 55 in FIGURES 2 and 3 to whichthe pipes 46 and 53 are attached is stationary and provides a bearingfor the roller shaft 47.

Referring now to FIGURE 4, the body of the suction roller 15 is built upof three pieces 56, 57 and 5S, and the pieces Sfi and 58 have longrectangular grooves made in them to provide the suction passages 54. Itwill be seen that these register with the passages 49 in the valve piece48 and thus suction through the pipe 53 is (subject to control by therotation of the valve piece 48) effective along these grooves 54, fromwhich suction ports 59 extend to the periphery of the roller.

As the roller rotates, the passages 49 in one part of the valve piece 48connect with slot 51 when said part is at its lowest position, seeFIGURE 2. Suction is thus exerted on a sheet from pipe 44 by ports 59,through passages 54, passages 49, slot 51, pipe 46, and hole 43. Thesheet therefore moves round with the roller a distance equal to are A,FIGURE 3, by which time, due to the overlap C, the suction through thesaid ports is continued by suction from pipe 53 through slot 52 theother set of passages 49 and the passages 54. The sheet is thereforeheld to the roller for rather more than half a revolution, as suctionceases at the upper end, FIGURE 3, of arc B. The leading end of thesheet can therefore be easily stripped by the belt 18 and strippingcontinues as the suction ports holding said sheet continue to be shutoff from suction by the valve piece movement.

This operation continues for such time as it takes to deliver 500 sheetsto the stacker by which time the valve disc 41 has rotated far enough toshut off the suction from pipe 44. This renders slot 51 inoperative andso no more sheets are picked up by the roller. The remainder pass alongto the second suction roller 27 where they are handled in much the samefashion. Meanwhile the valve disc 4-1 continues to rotate and, after afurther ten ratchet teeth movements during which time 500 sheets havecollected in stacker 29, suction wil be once more available from pipe 44so the sheets will again be carried up to the first stacker by theroller while the second stacker has its quota which can be removed. Nocontrol is therefore necessary on the second suction roller except thata bush, similar to the bush 5%, causes suction to be effective from aposition near the top of the roller round to the stripping position.This avoids wasted suction effort during roller movement from thestripping position to the top position of the roller.

When a web printing machine is first put into operation a considerablelength of web is run through before any is fit for use. It is thereforenecessary to dispose of defective sheets before serious work starts andto this end the mnaually operated valve 66, FIGURE 2, is provided. Asexplained earlier this valve is shut during normal operation but whensheets cut from a defective beginning of the web are to be separatedfrom the normal product, the valve is opened. In this way roller 15 willfeed sheets up to stacker 22 irrespective of the position of valve disc31. When satisfactory sheets are forthcoming the valve is shut. If thevalve disc is then in the appropriate position these sheets Willcontinue to pass to stacker 22 until the aperture 4-2 is closed. Then,as before, sheets will go to the stacker 29 and all sheets accumulatedin stacker 22, bad and good, are discarded. If however the valve disc 1snot in the appropriate position the good sheets succeeding the defectiveones will go to stacker 29 forming an incomplete stack which isdiscarded. Thereafter the stackers fill up alternately.

The fence 22A on stacker 22 may be raised and lowered automatically bymeans of an air cylinder 62. The fence is down all the time sheets areaccumulating in the stacker and for some time after the pile is completefor, say, while 50 sheets are collecting in stacker 29. It is thenraised by the air cylinder. When, say, 450 have collected in stacker 29the fence is lowered again. In the interval the operator removes thepile from 22 and the stacker is then ready to collect the new pile.

Control of the air cylinder may be by a valve system operated by aratchet wheel like 49, or even by said ratchet wheel, which can bearranged to open a valve after say one tooth has moved after valve disc41 has shut off suction to roller 15 and to open another valve to drivethe piston of the air cylinder in the reverse direction after eight moreratchet teeth have moved.

FIGURE 5 shows a suitable drive for the ratchet wheel 40. To the suctionroller shaft 47 is fixed a mitre gear wheel 71 engaging another mitregear wheel 72 on a shaft 73 having a worm '74 at one end. This wormengages a wormwheel 75 to which is fixed the cam which has a radial stepdown which a cam rod 76 can move under pressure of a spring 77. A pawl73 pivoted to the cam rod moves the ratchet wheel 40 sharply as the endof the cam rod snaps down the radial step.

Where, as will generally be the case, wide webs are being printed andthe suction rollers are of considerable length, the suction pipes andcontrol valves are duplicated, one set at each end of a roller, so as toequalise, as far as possible the pressure within the rollers.

What I claim as my invention and desire to secure by Letters Patent is:

1. In apparatus for stacking sheets of the kind comprising means forfeeding sheets in succession along a path, a rotatable suction rollermounted adjacent said path and arranged to remove the sheets insuccession therefrom, a source of suction for said roller, strippingmeans associated with the roller to remove each sheet therefrom and astacker adapted to receive the stripped sheets and stack them, means forcounting the sheets forming into a stack comprising a cam driven insynchronism with the suction roller, a ratchet Wheel intermittentlyrotatable by said cam and a rotatable valve interposed between saidsource of suction and the roller and rotated by the ratchet wheel,whereby said ratchet wheel will close said valve after said roller hasmade a predetermined number of revolutions from the commencement of thestack in operation, shutting off said roller from said source of suctionand preventing said roller from removing further sheets from said path.

2. Apparatus as claimed in claim 1 in which the stripping meanscomprises an endless belt which wraps around the roller for a part ofits circumference and extends away from the roller tangentially at thestripping position, the belt being arranged to lie inside the rollerperiphery so as to be out of contact with a sheet carried by the rolleruntil the stripping position is reached, at which position the beltengages the sheet to separate it from the roller.

3. In apparatus as claimed in claim 1, a second suction roller connectedto a source of suction and an associated stacker spaced along said pathfrom the first suction roller and stacker whereby when the ratchet wheelhas rotated the valve sufiiciently to shut off the first suction rollerfrom the source of suction, the following sheets continue along the pathand are removed and stacked by the second suction roller and associatedstacker, and after the first suction roller has again made thepredetermined number of revolutions the ratchet wheel opens the valve toagain connect the source of suction to the first suction roller, whichthereupon commences to remove sheets to be transferred to the firststacker.

4. Apparatus as claimed in claim 3 comprising a manually operated valveinterposed between the source of suction and the first suction rollerand which can be opened to by-pass the rotatable valve operated by theratchet wheel and render it ineffective, so that when the apparatus isfirst put into operation all sheets fed to it will be passed to thefirst stacker, irrespective of the position of said rotatable valve,said manually operated valve being closed when satisfactory sheets arebeing fed to the apparatus so that said rotatable valve is againeffective for sheet counting, any sheets collected in the first stackerduring the time from starting until the time at which said rotatablevalve shuts ofi the source of suction from the first suction rollerbeing discarded, while if said rotatable valve is positioned to shut oftthe source of suction from the first suction roller at the time themanual valve is closed, succeeding sheets will collect in the secondstacker and can be discarded as soon as the first suction rollercommences again to feed sheets to its stacker.

References Cited by the Examiner UNITED STATES PATENTS 2,759,543 8/56Conti 271-71 X 2,796,258 7/57 Beck 271-29 2,797,092 7/ 57 Welsh 271292,852,989 9/58 Chaplin et a1 93-93.3 2,867,438 1/59 Hori 271-743,006,258 10/61 Jockem 93-933 3,046,008 7/62 Velvel 271-68 3,051,3328/62 Richert et a1 27168 X 3,087,725 4/63 Duncan 27171 M. HENSCN WOOD,JR., Primary Examiner.

RAPHAEL M. LUPO, ROBERT B. REEVES,

Examiners.

1. IN APPARATUS FOR STACKING SHEETS OF THE KIND COMPRISIING MEANS FORFEEDING SHEETS IN SUCCESSION ALONG A PATH, A ROTATABLE SUCTION ROLLERMOUNTED ADJACENT SAID PATH AND ARRANGED TO REMOVE THE SHEETS INSUCCESSION THEREFROM, A SOURCE OF SUCTION FOR SAID ROLLER, STRIPPINGMEANS ASSOCIATED WITH THE ROLLER TO REMOVE EACH SHEETS THEREFROMAND ASTACKER ADAPTED TO RECEIVE THE STRIPPED SHEETS AND STACK THEM, MEANS FORCOUNTING THE SHEETS FORMING INTO A STACK COMPRISING A CAM DRIVEN INSYNCHRONISM WITH THE SUCTION ROLLER, A RATCHET WHEEL INTERMITTENTLYROTATABLE BY SAID CAM AND A ROTATABLE VALVE INTERPOSED BETWEEN SAIDSOURCE OF SUCTION AND THE ROLLER AND ROTATED BY THE RATCHET WHEEL,WHEREBY SAID RATCHET WHEEL WILL CLOSE SAID VALVE AFTER SAID ROLLER HASMADE A PREDETERMINED NUMBER OF REVOLUTIONS FROM THE COMMENCEMENT OF THESTACK IN OPERATION, SHUTTING OFF SAID ROLLER FROM SAID SOURCE OF SUCTIONAND PREVENTING SAID ROLLER FROM REMOVING FURTHER SHEETS FROM SAID PATH.